Closure assembly for a tank filler neck

ABSTRACT

A filler neck closure assembly for a vehicle fuel tank filler neck, comprising: a housing configured to be mounted in the filler neck and formed to include a sealing surface and a pressure-relief valve positioned to lie in the housing and provided with a nozzle-receiving portion and a sealing portion, wherein the nozzle-receiving portion is formed to include a nozzle-receiving opening sized to receive a pump nozzle during refueling of the fuel tank and the sealing portion is movable with the nozzle portion and relative to the housing between a closure-sealing position sealingly engaging the sealing surface and a pressure-relief position away from the sealing surface to define an opening to vent fuel vapor from the fuel tank when tank pressure exceeds a predetermined maximum pressure. The housing is formed to include a passageway containing the pressure-relief valve therein and defines an annular space around the pressure-relief valve, between the pressure-relief valve and the housing, and with a coiled compression spring positioned in the annular space, the pressure-relief valve including an axially outwardly extending annular guide wall adjacent to the annular space which defines a radially inner side of the annular space, the housing further including a radially inwardly extending annular lip wherein the guide wall slidingly engages the lip of the housing to radially guide the pressure-relief valve during movement of the pressure-relief valve between the closure-sealing position and the pressure-relief position.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a closure assembly for a tank fillerneck, and particularly to a capless closure assembly for a vehicle fueltank filler neck that operates to close the filler neck automatically assoon as a fuel-dispensing pump nozzle is removed from the filler neckfollowing refueling of the tank. More particularly, the presentinvention relates to a filler neck closure assembly that cooperates witha fuel-dispensing pump nozzle, which may be connected to a roboticrefueling system, to provide an automatic opening and closing mechanismfor the filler neck and that functions automatically to vent excess tankpressure and relieve unwanted tank vacuum after refueling is completed.

A removable fuel cap with a sealing gasket is typically used to closethe open end of a fuel tank filler neck. After an attendant fills thefuel tank and withdraws the pump nozzle from the filler neck, the fuelcap is attached to the filler neck so that the sealing gasket forms aseal between the fuel cap and the filler neck. Thus, the fuel cap closesthe open end of the filler neck to block discharge of liquid fuel andfuel vapor from the fuel tank through the filler neck. Additionally,some fuel caps are provided with pressure-relief and vacuum-reliefvalves to permit some controlled venting of fuel vapors in the fillerneck while the fuel cap is mounted on the filler neck.

It has been observed that fuel caps are often lost or damaged over timeand, as a result, the open end of the filler neck might not be closedand sealed in accordance with original equipment specifications duringoperations of the vehicle. Accordingly, a filler neck configured to“open” automatically as a fuel-dispensing pump nozzle is inserted intothe filler neck during refueling and “close” automatically once the pumpnozzle is withdrawn from the filler neck without requiring an attendantto reattach a fuel cap to the filler neck would be an improvement overmany conventional capped filler neck systems. .Although Althoughconventional fuel caps function to close filler necks in a satisfactorymanner, it is thought that a capless filler neck could make vehiclerefueling more convenient for consumers because no action other thaninserting a pump nozzle into the outer end of the filler neck would berequired to begin refueling a vehicle. Advantageously, such a caplessfiller neck system would be configured in accordance with the presentinvention to include a liquid fuel and fuel vapor control apparatus.

Filler necks with self-closing closure mechanisms are known in the art.See, for example, U.S. Pat. Nos. 3,938,564 to Jones: 5,056,570 to Harriset al.: and 5,271,438 to Griffin et al. In addition, U.S. Pat. Nos.5,195,566 to Ott et al.: 4,986,439 to Ott et al.: 4,702,839 to Boehmeret al.: and 4,424,839 to Otani et al., and German document Nos. DE 42 18287 A1 to Ott and DE 42 43 883 A1 to Soutter all disclose self-closingcaps.

A robotic refueling system operates to detect a vehicle arriving at avehicle-refueling station, locate a fuel tank filler neck in thevehicle, and move a fuel-dispensing pump nozzle automatically into andout of the filler neck at the proper times so that the fuel tank onboard the vehicle can be filled with fuel without any manual movement oroperation of the pump nozzle by an attendant. For example, U.S. Pat.Nos. 5,238,034 to Corfitsen: 3,642,036 to Ginsburgh, and 3,527, 268 toGinsburgh: as well as German document No. DE 42 42 243 A1 to Hagele alldisclose automatic fueling systems for vehicles provided with fillerneck closures suited for use with such systems.

A capless filler neck closure that is configured to control air, vapor,and liquid flow into and out of a fuel tank filler neck and iscompatible with robotic refueling systems, yet is configured to beassembled quickly and easily using a minimal number of parts would be animprovement over known filler neck closures. An inexpensive yeteffective capless filler neck closure that is reliable, easy tomanufacture, and easy to install is needed. This need is expected togrow once robotic refueling systems become widely available. A caplessfiller neck closure that is configured to open automatically in responseto engagement with a moving pump nozzle regardless of whether the pumpnozzle is moved manually by an attendant or robotically by a roboticrefueling system, and to close automatically after refueling iscompleted, and that is configured to relieve unwanted excess pressureand vacuum conditions in the tank automatically any time that suchconditions develop and the filler neck is closed, would be welcomed bymany vehicle manufacturers, vehicle owners, and service stationoperators.

According to the present invention, a filler neck closure assembly isprovided for a vehicle fuel tank filler neck. The filler neck closureassembly includes a housing configured to mount in the filler neck andformed to include a sealing surface. A pressure-relief valve is mountedfor movement in the housing and formed to include a nozzle-receivingportion and a sealing portion. The nozzle-receiving portion is formed toinclude an inner nozzle-receiving opening that receives a pump nozzleduring refueling of the fuel tank. The sealing portion normally engagesthe sealing surface formed in the housing.

The sealing portion of the pressure-relief valve is movable relative tothe housing between a closure-sealing position and a pressure-reliefposition in response to changing pressure conditions in the filler neckso as to relieve excess fuel vapor pressure that develops from time totime in the filler neck. Normally, the filler neck pressure is below apredetermined maximum pressure and the sealing portion of thepressure-relief valve is retained in the closure-sealing positionsealingly engaging the sealing surface to block discharge of liquid fueland fuel vapor from the filler neck to the atmosphere past thepressure-relief valve. However, when filler neck pressure exceeds thepredetermined maximum pressure, the sealing portion is moved by suchhigh pressure away from the sealing surface in the housing to thepressure-relief position to define a venting opening between the housingand the pressure-relief valve. This allows pressurized fuel vapor tovent from the fuel tank to the atmosphere through the vent opening.

The pressure-relief valve is configured so that the nozzle-receivingportion formed therein moves along with the sealing portion formedtherein when the sealing portion moves between the closure-sealingposition and the nozzle-receiving position to vent pressurized fuelvapor from the filler neck to the atmosphere. Illustratively, thesealing portion is arranged to surround the nozzle-receiving portion.

In preferred embodiments, the filler neck closure assembly is installedin the filler neck of a vehicle fuel tank. The filler neck closureassembly is a “capless system” because it does not include a traditionalfuel cap that is separate and removable from the filler neck.Significantly, the filler neck closure assembly is configured to allowan attendant or a robotic mechanism to insert a fuel-dispensing pumpnozzle into the filler neck during refueling of the fuel tank withoutfirst removing a separate fuel cap from the mouth of the filler neck. Inaddition, after refueling is completed and the pump nozzle is withdrawn,the closure assembly automatically closes the filler neck so that it isunnecessary for an attendant or a robotic mechanism to install aseparate fuel cap on the filler neck to close the mouth of the fillerneck.

Vehicles having fuel tanks are often operated in environments in whichfuel in the fuel tank experiences temperature fluctuations resulting infuel vapor pressure fluctuations in the fuel tank. The pressure-reliefvalve is mounted in the housing to relieve unwanted fuel vapor pressurein the fuel tank in excess of a predetermined maximum pressure that candevelop, for example, during operation of a vehicle in hot environments.

Illustratively, the pressure-relief valve in accordance with the presentinvention is a slidable, spring-loaded disk mounted at an outer end ofthe filler neck adjacent to the mouth of the filler neck. In addition, avacuum-relief valve is provided in the housing to relieve unwantedvacuum in the fuel tank. The vacuum-relief valve functions to admit airfrom the atmosphere into the filler neck so as to increase tank pressurewhen tank pressure is less than a predetermined minimum pressure. Vacuumconditions can develop in a fuel tank during the cool-down of a vehiclethat can occur, for example, at night. Illustratively, the vacuum-reliefvalve is a spring-loaded valve pivotably mounted on the pressure-reliefvalve.

The pressure-relief valve is formed to include a central opening that isnormally closed by the pivotable spring-loaded vacuum-relief valvemounted on the pressure-relief valve. During refueling, an attendant orrobotic mechanism passes a pump nozzle through the central openingformed in the pressure-relief valve and pivots the vacuum-relief valveto an opened position so that the pump nozzle can be used to dischargeliquid fuel into the fuel tank filler neck without disrupting theposition and filler-neck closing function of the pressure-relief valve.Normally, the sealing portion of the pressure-relief valve is urged by aspring to its closure-sealing position closing the filler neck duringrefueling. Advantageously, the pump nozzle can pass through the centralopening formed in the nozzle-receiving portion of the pressure-reliefvalve without disturbing or moving the surrounding sealing portion ofthe pressure-relief valve.

During fuel tank cool-down, excessive vacuum in the fuel tank and fillerneck creates a suction force in the filler neck sufficient to pivot thespring-loaded vacuum-relief valve away from is seat against thepressure-relief valve to an opened position. Such automatic “opening” ofthe vacuum-relief valve functions to allow a flow of air from theatmosphere into the fuel tank filler neck through the central openingformed in the pressure-relief valve, thereby relieving the unwanted lowtank and filler neck pressure automatically. This inflow of atmosphericair can occur even though the pressure-relief valve remains in a fillerneck-closing position.

In preferred embodiments, the closure assembly includes an outer shellconnected to the housing and positioned to lie adjacent to an outer sideof the slidable spring-loaded pressure-relief valve. The outer shell hasa front wall that defines a nozzle-guiding surface and that is formed toinclude a nozzle-receiving opening in fluid communication with thecentral opening formed in the adjacent pressure-relief valve. The frontwall is generally funnel-shaped so that a pump nozzle engaging thenozzle-guiding surface defined by front wall and advancing into theclosure assembly during refueling of the fuel tank is guided radiallyinwardly toward the nozzle-receiving opening formed in the outer shell.Advantageously, the nozzle-guiding surface on the front wall is helpfulboth to attendants manually guiding pump nozzles into the closureassembly and to robotic refueling systems automatically guiding pumpnozzles into the closure assembly. In addition, the front wall providesa seating surface to accommodate fuel vapor recovery nozzle assembliesthat include external fuel vapor recovery boots.

The closure assembly is easily installed into the filler neck of thefuel tank at the time of vehicle manufacture or repair. The installersimply grasps the outer shell of the closure assembly and places athreaded inner end of the housing into engagement with the threadedfiller neck. Rotation of the outer shell by the installer in a clockwiseclosure-advancing direction brings the threads on the housing intointerlocking engagement with the threads in the filler neck. Continuedrotation of the outer shell causes the outer shell and the housing unitto be drawn into the filler neck. Once the housing is properly seated inthe filler neck, the outer shell can be rotated or indexed relative tothe seated housing to assume a corrected installation orientation andposition on the filler neck.

An annular sealing gasket is provided on an outer portion of thehousing. As the installer rotates the outer shell and housing unit inthe closure-advancing direction, the closure assembly advances to atight seated position in the filler neck in which the sealing gasket istrapped between the filler neck and the housing to establish a liquidfuel and fuel vapor seal therebetween.

Advantageously, the closure assembly is designed and constructed toprotect the sealing gasket from damage that might be caused by overtightening the housing in the filler neck. The closure assembly isconfigured to divert excessive closure-advancing torque that aninstaller might apply to the outer shell away from the housing and thesealing gasket.

The torque-limiting mechanism interposed between the outer shell and thehousing allows torque applied to the outer shell below a predeterminedmaximum torque to be transmitted from the outer shell to the housing andtorque applied to the outer shell above the predetermined maximum torqueto be diverted away from the housing and the sealing gasket trappedbetween the housing and the filler neck. The torque-limiting mechanismcauses the outer shell to rotate independently of the housing when thetorque applied to the outer shell exceeds the predetermined maximumtorque, for example, when the installer continues to rotate the outershell after the closure assembly has advanced to the tight seatedposition in the filler neck, rather than transmitting the torque fromthe outer shell to the housing. The independent rotation of the outershell relative to the housing protects the sealing gasket while alsopermitting the installer to orient the outer shell in a proper radialinstallation position relative to the filler neck without affecting ordamaging the seal formed between the filler neck and the housing.

Advantageously, the radial orientation of the central opening of thepressure-relief valve relative to the outer shell is fixed by a splineappended to the pressure-relief valve and mounted in an opening of theouter shell. The spline cooperates with the outer shell to radially fixthe pressure-relief valve relative to the outer shell and to cause thepressure-relief valve to rotate relative to the housing in response torotation of the outer shell relative to the housing when the outer shellis rotated or indexed to assume the corrected installation orientationand position on the filler neck.

Additionally, a frangible connection between the outer shell and thehousing is designed and configured to enhance and control breakage ofthe closure assembly between the outer shell and the housing in a mannerthat is designed to leave the filler neck closed during an impact to theclosure assembly. A flange that connects the housing and the outer shellhas a frangible section to enhance breakage of the flange relative tothe housing. The closure assembly is configured so that the filler neckwill remain closed after the separation of the outer shell and theflange from the housing.

Also in preferred embodiments, various components of the closureassembly are decorated with selected codes, adornments, and/or patternsto facilitate detection of the filler neck and closure assembly. Forexample, the outer shell and a flapper door included in thevacuum-relief valve can cooperate to provide information useful forvisual detection of the location of the filler neck and closureassembly. The outer shell can be made from a material having a lightcolor and the flapper door can be made from a material having a darkcolor. Together, the outer shell and flapper door, which includes a flatplate that is visible behind the nozzle-receiving opening, can present a“bulls-eye” pattern that is easily recognizable by an attendant guidinga pump nozzle into the closure assembly.

Some robotic refueling systems use a filler neck detection system tolocate the filler neck for the robotic refueling system prior to dockingthe pump nozzle in the closure assembly. In these instances, codes,adornments, and/or patterns of the type described can provide dockingverification information that can be used by the robotic refuelingsystem.

Additional objects, features, and advantages of the invention willbecome apparent to those skilled in the art upon consideration of thefollowing detailed description of the preferred embodiments exemplifyingthe best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a perspective view of a vehicle including a fuel tank fillerneck closure assembly in accordance with the present invention and adiagrammatic illustration of a robotic refueling system including arefueling zone containing the vehicle a vehicle detector, a filler neckdetector, and a robotically-controlled pump nozzle connected to thefiller neck detector;

FIG. 2 is a perspective view of the fuel tank filler neck closureassembly of FIG. 1 showing an outwardly-facing nozzle-guiding surface ofthe closure assembly having a pump nozzle-receiving opening, a pumpnozzle moving toward the nozzle-guiding surface, and the expected path(represented by a dotted line) of a tip of the pump nozzle on thenozzle-guiding surface toward and into the nozzle-receiving openingformed in the closure assembly;

FIG. 3 is an exploded perspective view of the closure assembly of FIG. 1showing an outer shell including the nozzle-guiding surface, a housingincluding an annular outer body that is connectable to the outer shell,a threaded inner body that is connectable to the outer body, a basesized to receive the inner body and fit into an outer end of a fillerneck, an O-ring seal between the inner body and the base, and variouscomponents that can be arranged inside the housing to define aspring-loaded, annular, slidable pressure-relief valve and aspring-loaded, pivotable vacuum-relief valve in the closure assembly;

FIG. 4 is a sectional view taken along line 4—4 of FIG. 2 showing theslidable pressure-relief valve and the pivotable vacuum-relief valve intheir closed non-venting positions;

FIG. 4a is a partial sectional view of the spline and drive teeth shownat right angles to their locations in FIGS. 4;

FIG. 5 is a view of the closure assembly of FIG. 4 showing a pump nozzlepassing through the nozzle-receiving opening formed in the outer shell,holding a pivotable spring-biased flapper door in a fully openedposition, and dispensing liquid fuel into a fuel tank filler neck;

FIG. 6 is a view similar to FIG. 5 showing another type of pump nozzlepassing through the nozzle-receiving opening formed in the outer shelland dispensing liquid fuel into the fuel tank filler neck, this pumpnozzle carrying a fuel vapor recovery boot that is arranged to seatagainst a boot-seating surface on the outer shell when the pump nozzleis inserted into the filler neck during refueling of the fuel tank;

FIG. 7 is a view of the closure assembly of FIG. 4 showing the slidablepressure-relief valve after it has been moved in an axially outwarddirection in the closure assembly to a pressure-relief position due tothe presence of superatmospheric fuel vapor pressure in the filler neck,thereby permitting the flow of pressurized fuel vapor from a vehiclefuel tank through the filler neck and closure assembly to theatmosphere;

FIG. 8 is a view similar to FIG. 7 showing the spring-loaded, pivotableflapper door in the vacuum-relief valve after it has been pivoted in theclosure assembly to a vacuum-relief position due to the presence ofsubatmospheric fuel vapor pressure in the filler neck, therebypermitting the flow of ambient air from the atmosphere into the vehiclefuel tank through the closure assembly and filler neck;

FIGS. 9-13 show the outer shell of the closure assembly of FIG. 2 invarious positions as it is rotated relative to the filler neck toward apreferred orientation position after the installation of the housing andthe base into the filler neck;

FIG. 9 is a side elevation view of the closure assembly of FIG. 4 afteradvancing the closure assembly into the base by rotating the outer shellso that both a lip on the base and a lip on the closure assemblysealingly trap the O-ring seal therebetween but before the outer shellis rotated relative to the filler neck to a preferred orientation;

FIG. 10 is a front elevation view of the closure assembly of FIG. 9;

FIG. 11 is an enlarged sectional view taken along line 11—11 of FIG. 10showing a torque-override connection mechanism including drive teethappended to a bottom side of the outer shell and a flexible fingerappended to the housing, the finger having a driven tooth in engagementwith the drive teeth;

FIG. 12 is a side elevation view similar to FIG. 9 showing the outershell after it has been rotated about its axis of rotation relative tothe housing to its preferred orientation;

FIG. 13 is a front elevation view of the closure assembly of FIG. 12;

FIGS. 14-16 show a second embodiment of a closure assembly in accordancewith the present invention having a spring-loaded, annular, slidablepressure-relief valve formed to include a nozzle-receiving opening andan annular vacuum-relief valve seat and a sleeve inserted into thenozzle-receiving opening;

FIG. 14 is a view similar to FIG. 4 of the second embodiment of a fillerneck closure showing the annular valve seat for a spring-loaded,pivotable vacuum-relief valve inserted into the nozzle-receiving openingformed in the slidable pressure-relief valve and the sleeve insertedinto the nozzle-receiving opening and arranged to secure the valve seatin the nozzle-receiving opening;

FIG. 15 is a view similar to FIG. 14 showing the slidablepressure-relief valve after it has been moved in an axially outwarddirection to a pressure-relief position due to the presence ofsuperatmospheric fuel vapor pressure in the filler neck, therebypermitting the flow of pressurized fuel vapor from a vehicle fuel tankthrough the filler neck and closure assembly to the atmosphere;

FIG. 16 is a view similar to FIG. 15 showing a spring-loaded, pivotableflapper door in the vacuum-relief valve after it has been pivoted in theclosure assembly to a vacuum-relief position due to the presence ofsubatmospheric fuel vapor pressure in the filler neck, therebypermitting the flow of ambient air from the atmosphere into the vehiclefuel tank through the closure assembly and filler neck;

FIG. 17 is a view similar to FIGS. 4-8 showing the outer shell after ithas been broken away from the housing by an impact (represented by twodouble arrows) leaving the housing and a pressure control subassembly inthe housing intact and in a closed position continuing to close thevehicle filler neck;

FIG. 18 is a front elevation view of the outer shell of FIG. 12 and FIG.14 showing the nozzle-guiding surface of the outer shell cooperatingwith the flapper door to form a “bulls-eye” pattern as the closureassembly is seen by an external filler neck detector; and

FIG. 19 is a side elevation view of the closure assembly of FIG. 4 witha portion broken away showing a dust cover mounted on a fuel door of avehicle (not shown) in a position engaging the boot-seating surface ofthe outer shell to prevent dust from collecting in the closure assemblywhen the fuel door is closed.

DETAILED DESCRIPTION OF THE DRAWINGS

A closure assembly 10 in accordance with the present invention for afiller neck 12 of a vehicle fuel tank 14 is compatible for use both whenvehicle fuel tank 14 is refueled by an attendant (not shown) and whenvehicle fuel tank 14 is refueled using a robotic refueling system 16(shown diagrammatically in FIG. 1). In addition, closure assembly 10functions to vent excess fuel vapor pressure from vehicle fuel tank 14when tank pressure is too high and allow air into vehicle fuel tank 14when tank pressure is too low.

Illustrative robotic refueling system 16 is operable within a refuelingzone 18 illustratively shown by an area indicated by dashed lines inFIG. 1. When a vehicle 22 enter refueling zone 18 for refueling, avehicle detector 20 having an external nozzle-positioning sensor 28determines the position of vehicle 22 within refueling zone 18. Vehicledetector 20 also determines the approximate location of closure assembly10.

Once robotic refueling system 16 determines the approximate location ofclosure assembly 10, a pump nozzle assembly 82 appended to a pump nozzleconveyor 25 advances to the approximate location of closure assembly 10as shown in FIG. 2. A filler neck detector 26 for determining a moreprecise position of closure assembly 10 may be included with roboticrefueling system 16. Once the position of closure assembly 10 isestablished, pump nozzle conveyor 25 advances pump nozzle assembly 82toward closure assembly 10 so that a pump nozzle 24 can penetrateclosure assembly 10 and refuel vehicle fuel tank 14. Closure assembly 10is shown in more detail in FIGS. 3 and 4.

An exploded perspective view of closure assembly 10 of FIG. 2 isprovided in FIG. 3 to illustrate a preferred embodiment showing thevarious components of the closure assembly 10. An outer shell 30including a funnel-shaped front wall 70 arranged to define an outernozzle-receiving opening 74 is mounted on outer body 32. Outer body 32is connected to inner body 34. The outer and inner bodies 32, 34cooperate to define a housing 35 having an internal valve-receivingspace 26 as shown best in FIG. 4. Inner body 34 is received by a base 44that fits into a filler neck 12 and a sealing gasket or sealing member46 is positioned between inner body 34 and base 44 to sealingly engageboth inner body 34 and base 44 thereby blocking the flow of fuel vaporor ambient air therebetween.

It will be understood that the pressure in fuel tank 14 could increaseor decrease after filling due to changes, for example, in fueltemperature. As shown best in FIG. 3, a tank pressure controlsubassembly 38 includes a pressure-relief valve subassembly 40 and avacuum-relief valve subassembly 42. Tank pressure control subassembly 38is received in valve-receiving space 36 and configured to maintain thetank and filler neck pressure in a range between a predetermined minimumpressure and a predetermined maximum pressure.

Pressure-relief valve subassembly 40 includes a closure portionincluding a seal plate 132 having a nozzle-receiving portion 133 and asealing portion 135. Seal plate 132 is biased inwardly by a compressionspring or coiled compression spring 140 so that sealing portion 135sealingly engages an O-ring or annular seal or O-ring seal 138. O-ring138 is trapped between inner body 34 and sealing portion 135 toestablish a seal therebetween so that pressure-relief valve subassembly40. O-ring 138, and inner body 34 cooperate to block the flow of airinto fuel tank 14 and the flow of liquid fuel and fuel vapor out of fueltank 14 between sealing portion 135 and inner body 34 when the tankpressure is below the predetermined maximum tank pressure.

Sealing portion 135 of pressure-relief valve subassembly 40 is movablerelative to housing 35 and causes nozzle-receiving portion 133 to movealong with sealing or filler neck-closing or closed portion 135 betweenan axially inward closure-sealing position shown in FIG. 4 sealinglyengaging O-ring 138 and an axially outward pressure-relief or fillerneck-venting or open position shown in FIG. 7 away from O-ring 138 todefine an opening therebetween to vent fuel vapor from fuel tank 14 whentank pressure exceeds the predetermined maximum pressure.Nozzle-receiving portion 133 is formed to include an innernozzle-receiving opening or aperture 154 formed to receive the pumpnozzle 24 during refueling of fuel tank 14.

An axially inwardly extending upstanding annular seal-receiving wall 137is appended to seal plate 132 adjacent to inner nozzle-receiving opening154 as shown in FIGS. 3 and 4. Vacuum-relief valve subassembly 42includes an annular valve seat 134 mounted on seal-receiving wall 137and an annular door seal retainer 136 engages annular valve seat 134 toretain annular valve seat 134 against seal-receiving wall 137.Vacuum-relief valve subassembly 42 further includes a flapper door 180that is pivotably appended to seal plate 132 of pressure-relief valvesubassembly 40. It should be understood that vacuum-relief valvesubassembly 42 moves with seal plate 132 as the pressure-relief valvesubassembly 40 moves between the pressure-relief position shown in FIG.7 and the closure-sealing position shown in FIG. 4.

As shown in FIG. 4, flapper door 180 of vacuum-relief subassembly 42 isbiased axially outwardly by torsion spring 200 to a sealing positionsealingly engaging seal plate 132 to block the flow of air through theinner nozzle-receiving opening 154 when tank pressure is above thepredetermined minimum tank pressure. Flapper door 180 is drawn inwardlyaway from the sealing position when the tank pressure is below thepredetermined minimum pressure to pivot to a vacuum-relief or openposition shown in FIG. 8 away from seal plate 132 to form an openingtherebetween thereby allowing the flow of air through innernozzle-receiving opening 154 to fuel tank 14 to relieve subatmospherictank pressure. It can be seen, then, that vacuum-relief valvesubassembly 42 is movable relative to pressure-relief valve subassembly40 between the vacuum-relief position shown in FIG. 8 and the sealingposition shown in FIG. 4. It can also be seen that tank pressure controlsubassembly 38 operates to maintain the tank pressure in a predeterminedrange between the predetermined minimum pressure and the predeterminedmaximum pressure.

In addition to providing a path for the flow of ambient air throughfiller neck 12 and into vehicle fuel tank 14, inner nozzle-receivingopening 154 also receives pump nozzle 24 of vapor recovery nozzleassembly 82 as shown in FIG. 6 or a pump nozzle 23 of a standard nozzleassembly 81 as shown in FIG. 5 during refueling. The coaction betweenclosure assembly 10 and pump nozzle 23 is substantially similar to thecoaction between closure assembly 10 and pump nozzle 24. Alldescriptions of the coaction of both pump nozzles 23. 24 with closureassembly 10 below are presented with respect to pump nozzle 24 of vaporrecovery nozzle assembly 82 unless specifically stated otherwise.

Pump nozzle 24 engages flapper door 180 when pump nozzle 24 advancesinto closure assembly 10 and acts against torsion spring 200 to moveflapper door 180 to a fully open position shown in FIG. 6 duringrefueling. In this manner, vacuum-relief valve subassembly 42 cooperateswith inner nozzle-receiving opening 154 both to relieve subatmospherictank pressure below a predetermined minimum pressure and to allowingress of pump nozzle 24 into filler neck 12 during refueling.

Pump nozzle 24 can engage out shell 30 when moving to penetrate closureassembly 10. Outer shell 30 includes a cylindrical side wall 52 that isformed in the shape of a truncated right circular cylinder as shown inFIGS. 2-4. An inner edge 54 of cylindrical side wall 52 defines a circleand is positioned to lie in a plane that is perpendicular to a centralaxis 56 of cylindrical side wall 52. Cylindrical side wall 52 extendsaxially outwardly from inner edge 54. An axially outer edge 58 ofcylindrical side wall 52 is formed at an angle 60 to central axis 56 asshown in FIG. 4. Thus, cylindrical side wall 52 includes a short side 62and a long side 64 as shown in FIGS. 3 and 4. Angle 60 is selected tocorrespond to an angle 66 formed between a side wall 68 of vehicle fueltank 14 and filler neck 12 illustrated in FIG. 1 so that outer edge 58of cylindrical side wall 52 is essentially flush with body panels 53 ofvehicle 22.

Outer shell 30 further includes front wall 70 appended to outer edge 58of cylindrical side wall 52 as shown in FIGS. 2-4, and front wall 70 andcylindrical side wall 52 cooperate to define an enclosed space orinterior region 73 of outer shell 30 adjacent to a ratchet side 88 offront wall 70 as shown in FIG. 4. Front wall 70 includes an edge 72arranged to define outer nozzle-receiving opening 74. Front wall 70 isgenerally funnel-shaped thereby providing an outwardly-facingnozzle-guiding surface 76. As pump nozzle 24 advances toward outernozzle-receiving opening 74, it may engage nozzle-guiding surface 76 asshown in FIG. 2. The funnel-like shape of nozzle-guiding surface 76 actsto radially direct pump nozzle 24 toward outer nozzle-receiving opening74 as pump nozzle 24 advances into closure assembly 10. One illustrativepath that pump nozzle 24 could travel as pump nozzle 24 enters closureassembly 10 is represented by dashed line 77 shown in FIG. 2.

Nozzle-guiding surface 76 is shaped so that nozzle-guiding surface 76 isgenerally flat between short side 62 and edge 72 and is generallyS-shaped between long side 64 and edge 72, as shown in FIGS. 2-4. Thetransition of nozzle-guiding surface 76 radially between short side 62and long side 64 is gradual around the face of nozzle-guiding surface 76as shown best in FIGS. 2 and 3. The S-shape of nozzle-guiding surface 76provides a flat annular boot-seating surface 78 arranged to engage aboot 80 of a vapor recovery pump nozzle assembly 82 as shown in FIG. 6.Thus, front wall 70 is shaped both to direct advancing pump nozzle 24toward nozzle-receiving opening 74 as shown in FIG. 2 and to provideboot-seating surface 78 for boot 80 of vapor recovery pump nozzleassembly 82 as shown in FIG. 6.

Outer nozzle-receiving opening 74 is generally circular, as shown inFIGS. 2 and 3, though it is within the scope of the invention aspresently perceived to provide an outer nozzle-receiving opening 74 ofany shape so long as outer nozzle-receiving opening 74 is sized asdescribed below relative to other openings of closure assembly 10.Additionally, outer nozzle-receiving opening 74 includes a first centralaxis 84 illustrated in FIGS. 3 and 4 that is generally coincident withcentral axis 56 of cylindrical side wall 52. First central axis 84 maybe spaced-apart from central axis 56 so long as first central axis 84 ispositioned as described below relative to other openings of closureassembly 10.

Outer body 32 is appended to outer shell 30. Outer body 32 includes acylindrical side wall 106 having an axially outer edge 108 defining aninlet 104, shown best in FIGS. 3 and 4. Cylindrical side wall 106extends axially inwardly from outer edge 108 to an axially inner edge109 which is arranged to define inner opening 105. Cylindrical side wall106 is provided with a plurality of openings defining venting windows110 in fluid communication with an interior region 112 of outer body 32that is defined by cylindrical side wall 106 as shown in FIGS. 3 and 4.

A radially outwardly extending annular flange 100 is appended tocylindrical side wall 106 of outer body 32 at edge 108. Cylindrical sidewall 52 of outer shell 30 is formed to include a plurality of snaps 94having snap inner walls 98 and being positioned along a radially innersurface 96 of cylindrical side wall 52 as shown in FIGS. 3 and 4. Flange100 of outer body 32 has an edge 102 that snap-fits into outer shell 30so that snap inner walls 98 engage edge 102, thereby coupling outershell 30 to outer body 32. Snap inner walls 98 and edge 102 are ofradially uniform cross section so that edge 102 can slide along snapinner walls 98 to provide a rotatable coupling between outer shell 30and outer body 32.

Inner body 34 is formed to include a second cylindrical side wall 114arranged to define an outer opening 118, an outlet 120 opposite outeropening 118, and a second interior region 116 therebetween in fluidcommunication with outer opening 118 and outlet 120. Inner body 34 isconnected to outer body 32, and second cylindrical side wall 114 ofinner body 34 cooperates with cylindrical side wall 106 of outer body 32to define valve-receiving space 36 having a central axis 37 coincidentwith central axis 56 of outer shell 30 as shown in FIG. 4.

Inner body 34 includes a radially outwardly extending annular lip 122appended to second cylindrical side wall 114 adjacent to outer opening118. Lip 122 includes an axially outwardly facing first sealing surface124 and an axially inwardly facing second sealing surface 126. Outerbody 32 includes radially inwardly extending annular ledges 128 appendedto inner edge 109 as shown in FIGS. 3 and 4. Lip 122 of inner body 34snap-fits behind ledges 128 of outer body 32 so that second sealingsurface 126 engages ledges 128 to retain engagement between inner body34 and outer body 32 as shown in FIG. 4. Radially outwardly extendingtabs 130 are appended to lip 122 and are received by recesses 112 formedin cylindrical side wall 106 of outer body 32 as shown in FIG. 3 to keyinner body 34 to outer body 32 to eliminate rotational movement of innerbody 34 relative to outer body 32. Inner body 34 and outer body 32cooperate to form a housing 35.

Filler neck 12 includes a cylindrical wall 13 that defines an interiorregion 15. In preferred embodiments, base 44 is received by interiorregion 15. In addition, base 44 includes a cylindrical side wall 206that defines a closure-receiving space 210 as shown in FIGS. 3 and 4.Inner body 34 is received by closure-receiving space 210 of base 44.

Base 44 may also include an unleaded discriminator 205 as shown, forexample, in FIG. 4, to restrict penetration of pump nozzles 24 intofiller neck 12 to only those pump nozzles 24 connected to unleaded fuelsources. It is within the scope of the invention as presently perceivedto use closure assembly 10 in a filler neck of a vehicle fuel tank thatincludes a base that does not have unleaded discriminator 205 and infiller neck 12 of vehicle fuel tank 14 that includes base 44 havingunleaded discriminator 205.

It is also within the scope of the invention as presently perceived toeither mount closure assembly 10 directly in interior region 15 offiller neck 12 without interposing base 44 between closure assembly 10and filler neck 12, or to mount closure assembly 10 in base 44 which inturn is received by interior region 15 of filler neck 12 as shown inFIGS. 3 and 4. Advantageously, closure assembly 10 is well-suited foruse as a retrofit module for vehicle fuel tank filler necks configuredfor use with a fuel cap. Such vehicle fuel tank filler necks can easilybe modified by simply bringing threads or closure retainer apparatus 216formed on housing 35 into interlocking engagement with thread-engaginggrooves formed in the filler neck and rotating outer shell 30 in aclockwise closure-advancing direction 242. Rotation of outer shell 30causes housing 35 to rotate and to be drawn into the filler neck. Afterinstallation, the filler neck carries closure assembly 10 and can berefueled either by an attendant or by a robotic refueling system 16. Useof closure assembly 10 with base 44, which can be interposed betweenfiller neck 12 and closure assembly 10, is described below.

Cylindrical side wall 206 of base 44 is provided with thread-engaginggrooves 208 and is formed to include an axially outwardly-facing mouth212 and an axially inner edge 213. Unleaded discriminator 205 isappended to edge 213 and is formed to include nozzle-directing opening214 as shown in FIG. 4. Nozzle-directing opening 214 and mouth 212 arein fluid communication with closure-receiving space 210.

Second cylindrical side wall 114 of inner body 34 is formed to includethreads 216 that are received by thread-engaging grooves 208 whenclosure assembly 10 is received in closure-receiving space 210. Gasket46 is positioned to lie between mouth 212 and second sealing surface 126of annular lip 122 as shown in FIGS. 3 and 4 and is arranged to providea seal therebetween to block the flow of ambient air into filler neck 12or fuel vapor out of filler neck 12 between inner body 34 and base 44.This seal helps to ensure that the flow of fuel vapor out of fuel tank14 and the flow of ambient air into fuel tank 14 is directed throughtank pressure control subassembly 38.

Tank pressure control subassembly 38 includes pressure-relief valvesubassembly 40 which is positioned to lie within valve-receiving space36 formed by outer body 32 and inner body 34 of housing 35 as shown inFIGS. 3 and 4. Pressure-relief valve subassembly 40 includes annularseal plate 132 which is formed to include the sealing portion 135 andthe nozzle-receiving portion 133. O-ring 138 sealingly engages bothsealing portion 135 of seal plate 132 and first sealing surface 124 ofinner body 34 when the tank pressure is below the predetermined maximumpressure. Seal plate 132 of pressure-relief valve subassembly 40 isyieldably urged against O-ring 138 by compression spring 140 tosealingly engage O-ring 138 thereby preventing the flow of air into andfuel vapor out of the vehicle fuel tank 14 between seal plate 132 andO-ring 138.

Compression spring 140 is positioned inside of a compressionspring-receiving space 141 of valve-receiving space 36, as shown best inFIG. 4, to engage an axially outwardly-facing surface 142 of an annularlip 146 of seal plate 132 and an axially inwardly-facing surface 132 ofa radially inwardly extending annular lip 145 formed on edge 108 ofouter body 32. Outwardly-facing surface 142 of seal plate 132 andinwardly-facing surface 143 of outer body 32 define axially inner andaxially outer boundaries of compression spring-receiving space 141.Cylindrical side wall 106 of outer body 32 defines an axially outerboundary of compression spring-receiving space 141. Compression spring140 has a spring constant designed to yieldably urge the pressure-reliefvalve subassembly 40 inwardly against O-ring 138 provided on inner body34.

Seal plate 132 of pressure-relief valve subassembly 40 includes anupstanding annular guide wall 148 appended to outwardly-facing surface142 as shown in FIGS. 3 and 4. Guide wall 148 slidably engages lip 145and is positioned to lie inside of inlet 104 defined by lip 145 to guidethe radial movement of pressure relief valve subassembly 40 during axialoutward and inward movement of pressure-relief valve subassembly 40between the closure-sealing position shown in FIG. 4 and thepressure-relief position shown in FIG. 7. Guide wall 148 also defines anaxially inner boundary of compression spring-receiving space 141.

Axially outwardly-facing nozzle-directing ribs 150 are appended tooutwardly-facing surface 142 of nozzle-receiving portion 133 as shown inFIGS. 3 and 4. Each nozzle-directing rib 150 has a top surface 151 thatis angled relative to outwardly-facing surface 142. Top surface 151extends from a proximal end 153 positioned to lie inside of innernozzle-receiving opening 154 to a distal end 155 radially outward ofinner nozzle-receiving opening 154. Top surface 151 adjacent to distalend 155 of each nozzle-directing rib 150 is positioned to lie axiallyoutwardly of both proximal end 153 and of outwardly-facing surface 142.Top surfaces 151 cooperate to radially direct pump nozzle 24 towardinner nozzle-receiving opening 154 when pump nozzle 24 enters closureassembly 10 to refuel vehicle fuel tank 14.

Nozzle-receiving portion 133 of seal plate 132 includes innernozzle-receiving opening 154 and axially inwardly directed upstandingannular seal-receiving wall 137 appended to axially inwardly-facingsurface 144 of seal plate 132 as shown in FIG. 4. Seal-receiving wall137 encircles inner nozzle-receiving opening 154. In addition, axiallyinwardly directed arcuate retainer-engaging walls (not shown) areappended to seal plate 132 and are positioned to lie radially outward ofseal-receiving wall 137. Retainer-engaging walls are formed to includelug-receiving openings (not shown).

Annular valve seat 134 is received by seal-receiving wall 137 as shownin FIG. 4. Annual valve seat 134 includes an axially inwardly facingannular flapper door-seating surface 156, an axially outwardly facingannular seal plate-engaging wall 158, and a wall-engaging portion 160therebetween. Flapper door-seating surface 156, wall-engaging portion160, and seal plate-engaging wall 158 cooperate to define an annulargroove 162. A retainer 136 is received in groove 162 and cooperates withseal-receiving wall 137 to retain annular valve seat 134 againstseal-receiving wall 137 are shown in FIG. 4. Radially outwardly directedlugs 139 are appended to retainer 136 as shown in FIG. 3 and arereceived by lug-receiving openings (not shown) to hold retainer 136against seal plate 132.

Flapper door 180 is pivotably appended to seal plate 132 ofpressure-relief valve subassembly 40 as shown in FIGS. 3 and 4 toprovide closure assembly 10 with a door mechanism. Flapper door 180includes two spaced-apart axially inwardly extending arms 182. Sealplate 132 also includes two spaced-apart axially inwardly extending arms186 that are arranged to define a flapper door arm-receiving space 184therebetween as shown in FIG. 3. Arms 182 of flapper door 180 arereceived by flapper door arm-receiving space 184 of seal plate 132.Shaft-receiving openings 188 are formed in arms 182 of flapper door 180and shaft-receiving openings 190 are formed in arms 186 of seal plate132. Shaft-receiving openings 188, 190 are arranged to lie along astraight line. Pivot shaft 192 is rotatably received by shaft-receivingopenings 188, 190 as shown, for example, in FIGS. 3 and 4 so thatflapper door 180 can pivot about pivot shaft 192.

Flapper door 180 includes a circular plate 194 appended to arms 182.Circular plate 194 includes a circumferential sealing surface 196 thatengages flapper door-seating surface 156 when flapper door 180 is in asealing position as shown, for example, in FIG. 4. Circular plate 194also includes a raised axially outwardly directed nozzle-engagingsurface 198. Nozzle-engaging surface 198 engages pump nozzle 24 whenpump nozzle 24 penetrates closure assembly 10.

Flapper door 180 is yieldably urged against annular valve seat 134 bytorsion spring 200 to prevent the flow of air into or fuel vapor out ofvehicle fuel tank 14 between the flapper door 180 and annular valve seat134 when tank pressure is above the predetermined minimum tank pressure.Torsion spring 200 is coiled about pivot shaft 192 and includes a firstend 187 engaging one arm 186 of seal plate 132 and a second end 189engaging an inwardly directed surface 202 of flapper door 180. Torsionspring 200 has a spring constant designed to yieldably urge the flapperdoor 180 outwardly against annular valve seat 134.

Torsion spring 200 is specifically selected to have a spring constantsuch that circular plate 194 of flapper door 180 sealingly engagesannular valve seat 134 when the tank pressure is above the predeterminedminimum pressure and such that circular plate 194 disengages fromannular valve seat 134 when tank pressure is below the predeterminedminimum pressure to form an opening therebetween. Torsion spring 200 ispositioned to lie in housing 35 and is formed to include a central axis201 arranged to lie along a line that is perpendicular to central axis37 of housing 35.

Closure assembly 10 is positioned in filler neck 12 of vehicle fuel tank14 to receive pump nozzle 23 as shown in FIG. 5 or pump nozzle 24 asshown in FIG. 6. As pump nozzle 23, 24 penetrates closure assembly 10,camming engagement of pump nozzle 23, 24 with flapper door 180 forcesflapper door 180 inwardly against the outward bias of torsion spring 200to assume a fully opened nozzle-received position having nozzle-engagingsurface 198 in engagement with nozzle 23, 24. Nozzle-engaging surface198 prevents contact between pump nozzle 23, 24 and sealing surface 196of flapper door 180. Minimizing contact between sealing surface 196 andpump nozzle 23, 24 or other foreign objects reduces the risk of damageto or contaminating of sealing surface 196.

A standard pump nozzle assembly 81 can include a collar 83 mounted topump nozzle 23 as shown in FIG. 5. Collar 83 can be formed to include anaxially outer wall 85. Front wall 70 of outer shell 30 is formed toinclude a latching portion 71 adjacent to outer nozzle-receiving opening74, as shown in FIG. 5. Latching portion 71 is positioned to engageouter wall 85 of collar 83 after pump nozzle 23 is inserted into closureassembly 10 to prevent pump nozzle 23 from inadvertently sliding axiallyoutward out of closure assembly 10. Once refueling is complete, pumpnozzle 23 is released from closure assembly 10 by lifting pump nozzle 23to move collar 83 to a position that is radially inward of latchingportion 71 and moving pump nozzle 23 axially outwardly and away fromclosure assembly 10.

Pump nozzle 24 of vapor recovery nozzle assembly 82 is connected to boot80 as shown in FIG. 6. Front wall 70 of outer shell 30 is contoured toprovide boot-seating surface 78 so that boot 80 can seat against frontwall 70 to minimize the escape of fuel vapor between boot 80 andboot-seating surface 78 during refueling of vehicle fuel tank 14.

Typically, vapor recovery pump nozzle assembly 82 further includes acatch 91 having an axially outwardly-facing outer wall 92. Catch 91 istypically connected to pump nozzle 24 as shown in FIG. 6. Outer wall 92engages latching portion 71 after pump nozzle 24 is inserted intoclosure assembly 10 to prevent pump nozzle 24 from sliding axiallyoutwardly out of closure assembly 10 during refueling of fuel tank 14.Once refueling is complete, pump nozzle 24 is released from closureassembly 10 by lifting pump nozzle 24 to move outer wall 92 to aposition that is radially inward of latching portion 71 and moving pumpnozzle 24 axially outwardly and away from closure assembly 10.

When either an attendant or a robotic refueling system 16 prepares torefuel vehicle 22, pump nozzle 24 is directed toward closure assembly10. Front wall 70 of outer shell 30 is contoured to provide afunnel-like nozzle-guiding surface 76 arranged to direct advancing pumpnozzle 24 toward outer nozzle-receiving opening 74. After passingthrough nozzle-receiving opening 74, a tip 232 of advancing pump nozzle24 engages nozzle-engaging surface 198 of flapper door 180.

Camming engagement of pump nozzle 24 and nozzle-engaging surface 198caused by the advancement of pump nozzle 24 causes tip 232 to actagainst torsion spring 200 to force flapper door 180 into the fully openrefueling position shown in FIG. 5. In addition, torsion spring 200 actsthrough flapper door 180 to bias pump nozzle 24 downwardly therebydirecting pump nozzle 24 toward nozzle-directing opening 214 of base 44.Pump nozzle 24 continues to advance until tip 232 penetratesnozzle-directing opening 214 and, for vapor recovery pump nozzleassembly 82, until boot 80 engages boot-seating surface 78 as shown inFIG. 6.

Nozzle-directing opening 214 of base 44 is formed to include a thirdcentral axis 234 that is typically spaced apart from a central axis 215of filler neck 12 as shown in FIG. 4. Central axis 215 of filler neck 12is typically coincident with central axis 56 of outer shell 30 and firstcentral axis 84 of outer nozzle-receiving opening 74 of outer shell 30.Third central axis 234 is typically spaced apart from first central axis84 of outer nozzle-receiving opening 74 as illustrated in FIG. 4.

In addition, inner nozzle-receiving opening 154 of seal plate 132 isformed to include a second central axis 236. Second central axis 236 isalso typically spaced-apart from first central axis 84 of outernozzle-receiving opening 74. Second central axis 236 is positioned sothat inner nozzle-receiving opening 154 receives advancing pump nozzle24 from outer nozzle-receiving opening 74 and then guides advancing pumpnozzle 24 to nozzle-directing opening 214 of base 44 as shown in FIGS. 5and 6.

Inner nozzle-receiving opening 154 is sized and second central axis 236of inner nozzle-receiving opening 54 is spaced apart from first centralaxis 84 so that sufficient overlap of outer nozzle-receiving opening 74and inner nozzle-receiving opening 154 is present in an axial directionto permit pump nozzle 24 to be received by both first nozzle-receivingopening 74 and inner nozzle-receiving opening 154. Likewise,nozzle-directing opening 214 is sized and third central axis 234 isspaced apart from first central axis 84 and second central axis 236 sothat sufficient overlap of outer and inner nozzle-receiving openings 74,154 and nozzle-directing opening 214 is present in an axial direction topermit pump nozzle 24 to be received by all three of outer and innernozzle-receiving openings 74, 154 and nozzle-directing opening 214 asshown in FIGS. 5 and 6. However, it is within the scope of the inventionas presently perceived to provide a closure assembly having two or allthree of the first, second, and third central axes 84, 236, 234coincident.

In operation, when vehicle 22 is not being refueled, pressure-reliefvalve subassembly 40 permits fuel vapor from the vehicle fuel tank 14,designated by arrows 238 of FIG. 7, to vent from vehicle fuel tank 14when the pressure inside of vehicle fuel tank 14 is above thepredetermined maximum pressure as indicated by double arrow 239 of FIG.7. Under normal tank pressure conditions with tank pressure below thepredetermined maximum pressure a shown in FIG. 4, pressure-relief valvesubassembly 40 is in its closure-sealing position having inwardly facingsurface 144 of annular lip 146 of seal plate 132 yieldably urged againstO-ring 138 by compression spring 140 blocking the flow of fuel vaporbetween inlet 104 and outlet 120 of housing 35 thereby preventing theflow of fuel vapor 238 out of vehicle fuel tank 14.

Seal plate 132 is urged outwardly away from O-ring 138 in response topressure against flapper door 180 and seal plate 132 in excess of apredetermined superatmospheric pressure. Movement of seal plate 132 awayfrom O-ring 138 opens the vent passageway allowing for the discharge offuel vapor 238 from the vehicle fuel tank 14, through outlet 120 intoclosure assembly 10, between O-ring 138 and seal plate 132, and out ofventing windows 110 of outer body 32 as shown in FIG. 7. Once sufficientfuel vapor 238 has been discharged from vehicle fuel tank 14 to lowerthe pressure in vehicle fuel tank 14 below the predetermined maximumtank pressure, compression spring 140 yieldably urges annular lip 146 ofseal plate 132 inwardly against O-ring 138.

In addition, vacuum-relief valve subassembly 42 permits ambient air fromthe atmosphere outside the closure assembly 10, designated by arrows 240of FIG. 8, to enter vehicle fuel tank 14 when the pressure inside ofvehicle fuel tank 14 is below a predetermined minimum pressure asindicated by double arrow 241 of FIG. 8. Under normal tank pressureconditions with tank pressure above the predetermined minimum pressure,sealing surface 196 of flapper door 180 is yieldably urged againstflapper door seating surface 156 of annular valve seat 134 by torsionspring 200, thereby providing a seal to block the flow of fuel vapor 238out of or ambient air 240 into the vehicle fuel tank 14 through innernozzle-receiving opening 154 of pressure-relief valve subassembly 40 asshown in FIG. 4.

In its sealing position, flapper door 180 provides a seal betweensealing surface 196 and flapper door-seating surface 156. Once thepressure in vehicle fuel tank 14 decreases below the predeterminedsubatmospheric pressure, flapper door 180 is drawn inwardly, pivotingaway from annular valve seat 134 and allowing the flow of ambient air240 from outside of the vehicle fuel tank 14, through inlet 104 and intovalve-receiving space 36, through inner nozzle-receiving opening 154,through outlet 120, and into vehicle fuel tank 14 as shown in FIG. 8.Once sufficient ambient air 240 has entered vehicle fuel tank 14 toraise the pressure in vehicle fuel tank 14 above the predeterminedminimum tank pressure, torsion spring 200 yieldably urges flapper door180 against annular valve seat 134.

Installation of closure assembly 10 into closure-receiving space 210illustrates in FIGS. 9-13 is simplified by a torque-override connectionbetween outer shell 30 and outer body 32 that ensures properinstallation of closure assembly 10 in closure-receiving space 210.Flange 100 of outer body 32 includes six peripherally and slightlyaxially outwardly extending resilient fingers 220 each having a driventooth 222. Driven teeth 222 are equally spaced about the circumferenceof flange 100 to serve as engaging means to receive torque from outershell 30. Driven teeth 222 each include an inclined face 224 and anupright face 226.

Outer shell 30 also includes a plurality of inclined drive teeth 86spaced equally about the circumference of ratchet side 88 of front wall70 of outer shell 30 to serve as engaging means for propelling flange100 about axis of rotation 56 through engagement with driven teeth 222as shown in FIGS. 3, 4, and 11. Drive teeth 86 each include an inclinedface 228 and an upright face 230. Each upright face 230 cooperates withthe inclined face 228 of the next adjacent tooth 86 to define aninterdental pocket 87.

A person wishing to install closure assembly 10 in base 44 at a time ofvehicle manufacture or repair grasps outer shell 30 and applies torquethereto in a clockwise closure-advancing direction designated by arrow242 in FIG. 3. Torque is transmitted to flange 100 by the engagement ofdrive teeth 86 against driven teeth 222. Resilient fingers 220 biasdriven teeth 222 toward front wall 70, thus biasing driven teeth 222against drive teeth 86 to establish a torque-transmitting connection.Closure-advancing torque transmitted to outer shell 30 by engagement ofinclined faces 228 of drive teeth 86 and inclined faces 224 of driventeeth 222, as shown in FIG. 10, is further transmitted to flange 100,outer body 32, and inner body 34.

As the installer continues to apply torque in closure-advancingdirection 242, threads 216 of inner body 34 interlock withthread-engaging grooves 208 formed on base 44 so that closure assembly10 advances to a tight seated position in base 44 in which annulargasket 46 is trapped between the mouth 212 of base 44 and sealingsurface 126 of inner body 34 to establish a seal between the inner body34 and base 44 as shown in FIG. 9. Note, however, that outer shell 30may by oriented in a position other than the preferred orientation whenclosure assembly 10 achieves the tight seated position in base 44 asshown in FIG. 10 where outer shell 30 is at an angle 246 away from thedesired orientation.

Advantageously, closure assembly 10 is designed to accommodateadditional closure-advancing torque which an installer might apply. Whenclosure assembly 10 is advanced to a tight seated position, inner body34 is no longer able to rotate with respect to base 44. Thus,closure-advancing torque applied to outer shell 30 and transmitted toflange 100 in the above-described manner cannot be further transmittedto inner body 34. Therefore, each additional increment ofclosure-advancing torque applied to outer shell 30 translates to anadditional increment of engaging force applied by drive teeth 86 todriven teeth 222. Since the torque cannot be translated into rotationalmotion, it builds up in outer shell 30 to the point at which the torqueovercomes the frictional forces between drive teeth 86 and driven teeth222. Resilient fingers 220 flex so that driven teeth 222 can moverelative to drive teeth 86 out of interdental pockets 87 along inclinedfaces 224, 228, as shown in FIG. 11.

Owing to the relative angles of inclined faces 228, 224 of drive teeth86 and driven teeth 222, respectively, the movement of drive teeth 86relative to driven teeth 222 biases resilient fingers 220 axiallyinwardly. Continued application of torque will cause each driven tooth222 to move from its original interdental pocket 87 to the adjacentinterdental pocket 87, at which point each resilient finger 220 willbias each driven tooth 222 axially outwardly so that each driven tooth222 is presented for driving engagement with an adjacent drive tooth 86.

If additional closure-advancing torque is applied to outer shell 30driven teeth 222 will continue to move relative to drive teeth 86 asabove-described with a characteristic “clicking” noise. That is, outershell 30 will essentially rotate freely with respect to flange 100 andwill thus absorb excess torque while maintaining the seal between innerbody 34 and base 44 intact.

The torque-overriding connection prevents over tightening of inner body34 in base 44, thereby ensuring that gasket 46 sealingly engages bothsecond sealing surface 126 and mouth 212. It also allows for therotation of outer shell 30 after installation of closure assembly 10into filler neck 12 to adjust the orientation of outer shell 30 so thatthe short side 62 is positioned generally below long side 64 as shown inFIGS. 11 and 12, and outer edge 58 of cylindrical side wall 52 isessentially flush with vehicle body panels 53.

Although in preferred embodiments first central axis 84 of outernozzle-receiving opening 74 is coincident with central axis 56 of outershell 30, second central axis 236 of inner nozzle-receiving opening 154is spaced-apart from central axis 56 of outer shell 30. Improperorientation of second central axis 236 of inner nozzle-receiving opening154 could make it difficult for a user to insert pump nozzle 24 intoclosure assembly 10. Advantageously, closure assembly 10 is configuredto orient pressure-relief valve subassembly 40 thereby orienting innernozzle-receiving opening 154 when the user orients outer shell 30.

Outer shell 30 is provided with two axially-inwardly directed lugs 248appended to ratchet side 88 of front wall 70 as shown in FIG. 4.FIG. 4and FIG. 4A.

Two axially outwardly directed splines 252 are appended to seal plate132 adjacent to guide wall 148 as shown in FIGS. 3 and 4. The lugs 248are spaced apart so that the spline-receiving space 250 receives thesplines 252. Each spline 252 engages a lug 250, thereby eliminatingindependent rotational movement of outer shell 30 relative to seal plate132 of pressure-relief valve subassembly 40. Pressure-relief valvesubassembly 40 rotates with outer shell 30 relative to housing 35 whenthe user applies sufficient closure-advancing torque to cause outershell 30 to rotate relative to housing 35.

Although it should not frequently be necessary to remove closureassembly 10 from closure-receiving space 210, a torque-transmittingconnection can be established in a closure-removal direction representedby arrow 244 in FIGS. 3 and 11. In removal of closure assembly 10, driveteeth 86 engage driven teeth 222 to provide a positive connectionbetween flange 100 and outer shell 30. As shown in FIG. 11, when torqueis applied to outer shell 30 to rotate closure assembly 10 inclosure-removal direction 244, the torque is transmitted to flange 100by way of engagement of upright faces 230 of drive teeth 86 againstupright faces 226 of driven teeth 222. Since it is not necessary toaccommodate excess torque in closure removal, upright faces 226, 230 canbe provided for the torque-transmitting connection rather than inclinedfaces 224, 228 as are provided to establish the closure-advancingconnection. The cooperation of resilient fingers 220, drive teeth 86,and driven teeth 222 to provide a torque-overriding connection in onedirection and a direct connection in the other direction is well knownin the art, and is specifically described in U.S. Pat. Nos. 4,280,346 toEvans and 5,110,003 to MacWilliams, the entire disclosures of which arehereby incorporated by reference.

A second embodiment of a closure assembly 310 including a secondembodiment of a tank pressure control subassembly 338 is shown in FIGS.14-16. Closure assembly 310 includes outer shell 30 having front wall 70which is formed to include nozzle-guiding surface 76 and outernozzle-receiving opening 74. Outer shell 30 is rotatably connected toouter body 32 of housing 35. Outer body 32 and inner body 34 of housing35 cooperate to define valve-receiving space 36. Tank pressure controlsubassembly 338 including pressure-relief valve subassembly 340 andvacuum-relief valve subassembly 342 is received by valve receiving space36.

Pressure-relief valve subassembly 340 includes an annular seal plate 332formed to include a nozzle-receiving portion 33 and a sealing portion335. Seal plate 332 is biased inwardly by a compression spring 140 sothat sealing portion 335 sealingly engages an O-ring 138. O-ring 138 istrapped between the first sealing surface 124 of inner body 34 andsealing portion 335 to establish a seal therebetween so thatpressure-relief valve subassembly 340. O-ring 138, and inner body 34cooperate to block the flow of air into fuel tank 14 and the flow offuel vapor out of fuel tank 14 between sealing portions 335 and innerbody 34 when the tank pressure is below the predetermined maximum tankpressure.

Sealing portion 335 of pressure-relief valve subassembly 340 is movablerelative to housing 35 and causes nozzle-receiving portion 333 to movealong with sealing portion 335 between an axially inward closure-sealingposition shown in FIG. 14 sealingly engaging O-ring 138 and an axiallyoutward pressure-relief position shown in FIG. 15 away from O-ring 138to define an opening therebetween to vent fuel vapor from fuel tank 14when tank pressure exceeds the predetermined maximum pressure.Nozzle-receiving portion 333 is formed to include an innernozzle-receiving opening 354 formed to receive the pump nozzle 24 duringrefueling of fuel tank 14.

Vacuum-relief valve subassembly 342 includes an annular valve seat 134mounted in inner nozzle-receiving opening 354 and an annular doorseal-retainer sleeve 356 engaging annular valve seat 134 and positionedto lie in inner nozzle-receiving opening 354 as shown in FIGS. 14 and16. Vacuum-relief valve subassembly 342 further includes a flapper door180 that is pivotably appended to seal plate 332 of pressure-reliefvalve subassembly 340. It should be understood that vacuum-relief valvesubassembly 342 moves with seal plate 332 as the pressure-relief valvesubassembly 340 moves between the pressure-relief position shown in FIG.15 and the closure-sealing position shown in FIG. 14.

Flapper door 180 of vacuum-relief subassembly 342 is biased axiallyoutwardly by torsion spring 200 to a sealing position shown in FIG. 14sealingly engaging seal plate 332 to block the flow of air through theinner nozzle-receiving opening 354 when tank pressure is above thepredetermined minimum tank pressure. Flapper door 180 is drawn inwardlyaway from the sealing position when the tank pressure is below thepredetermined minimum pressure to pivot to the vacuum-relief positionshown in FIG. 16 away from seal plate 332 to form an openingtherebetween thereby allowing the flow of air through innernozzle-receiving opening 354 to fuel tank 14 to relieve subatmospherictank pressure.

Seal plate 332 of pressure-relief valve subassembly 340 includes anupstanding annular guide wall 348 appended to an outwardly-facingsurface 336 as shown in FIG. 14. Guide wall 348 slidably engages lip 145and is positioned to lie inside of inlet 104 defined by lip 145 to guidethe radial movement of pressure relief valve subassembly 340 duringaxial outward and inward movement of pressure-relief valve subassembly340 between the closure-sealing position shown in FIG. 14 and thepressure-relief position shown in FIG. 15.

Nozzle-receiving portion 333 of seal plate 332 includes a radiallyinwardly extending ledge 350 having an inner edge 352 defining innernozzle-receiving opening 354 as shown in FIG. 14. Annular valve seat 134is inserted into inner nozzle-receiving opening 354 so that ledge 350 isreceived in groove 162 of annular valve seat 134. A door seal-retainersleeve 356 is inserted in inner nozzle-receiving opening 354 andcooperates with ledge 350 to retain annular valve seat 134 against inneredge 352 as shown in FIGS. 14-16.

Door seal-retainer sleeve 356 includes an axially inner annular wall 364engaging wall-engaging portion 160 of annular valve seat 134 as shown inFIG. 14. Door seal-retainer sleeve 356 further includes an axially outerannular wall 366 engaging seal plate-engaging wall 158 of annular valveseat 134. Outer annular wall 366 is formed to include axially inwardlyopening notches 368 that engage axially outwardly directed tabs 370formed in outwardly facing surface 336 of seal plate 332. Notches 368cooperate with tabs 370 and inner annular wall 164 of seal plate 332cooperates with wall-engaging portion 160 of annular valve seat 134 toretain door seal-retainer sleeve 356 in snap-fit engagement with sealplate 332, thereby retaining annular valve seat 134 against inner edge352 of seal plate 332 as shown in FIG. 14.

Outer annular wall 366 of door seal-retainer sleeve 356 is formed tofurther include a funnel-shaped top surface 372 surrounding innernozzle-receiving opening 354 as shown in FIG. 14. As pump nozzle 24advances from outer nozzle-receiving opening 74 toward innernozzle-receiving opening 354 it may engage top surface 372. Thefunnel-like shape of top surface 372 acts to radially direct pump nozzle24 toward inner nozzle-receiving opening 354 as pump nozzle 24 advancesinto closure assembly 10 when pump nozzle 24 enters closure assembly 10to refuel vehicle fuel tank 14.

Flapper door 180 is pivotably appended to seal plate 332 ofpressure-relief valve subassembly 40 as shown in FIGS. 14 and 16.Flapper door 180 includes two spaced-apart axially inwardly extendingarms 182. Seal plate 332 also includes two spaced-apart axially inwardlyextending arms 386 that are arranged to define a flapper doorarm-receiving space 384 therebetween as shown in FIG. 14. Arms 182 offlapper door 180 are received by flapper door arm-receiving space 384 ofseal plate 332. Shaft-receiving openings 188 are formed in arms 182 offlapper door 180 and shaft-receiving openings 390 are formed in arms 386of seal plate 332. Shaft-receiving openings 188, 390 are arranged to liealong a straight line. Pivot shaft 192 is rotatably received byshaft-receiving openings 188, 190 as shown, for example, in FIG. 14 sothat flapper door 180 can pivot about pivot shaft 192.

Flapper door 180 is yieldably urged against annular valve seat 134 bytorsion spring 200 to prevent the flow of air into or fuel vapor out ofvehicle fuel tank 14 between the flapper door 180 and annular valve seat134 when tank pressure is above the predetermined minimum tank pressure.Torsion spring 200 is coiled about pivot shaft 192 and includes a firstend 187 engaging one arm 386 of seal plate 332 and a second end 189engaging an inwardly directed surface 202 of flapper door 180. Torsionspring 200 has a spring constant designed to yieldably urge the flapperdoor 180 outwardly against annular valve seat 134.

Advantageously, in both closure assembly 10 and closure assembly 310,flange 100 is configured to enhance separation of flange 100 from edge108 of outer body 32 if closure assembly 10 is subjected to an impactgreater than a predetermined magnitude, represented by arrow 258 andarrow 259, both of which represent impacts that could cause flange 100to separate from housing 35 as shown in FIG. 17. Flange 100 is formed toinclude a frangible section 254 arranged to enhance breakage of closureassembly 10 at frangible section 254, shown in FIGS. 4, 14, and 17.Flange 100 is formed to include annular groove 256 adjacent to edge 108of cylindrical side wall 106 as shown in FIGS. 3 and 4. Annular groove256 is sized to form frangible section 254 adjacent to groove 256 toenhance the probability that flange 100 will separate from cylindricalside wall 106 adjacent to groove 256 rather than other elements ofclosure assembly 10.

Separation of flange 100 from outer body 32 at frangible section 254will result in the separation of outer shell 30 and flange 100 fromclosure assembly 10 along fracture line 255 as shown in FIG. 17.Pressure-relief valve subassembly 40, vacuum-relief valve subassembly42, annular slip 145 of outer body 32, and annular lip 122 of inner body34 will not be affected by removal of flange 100. Compression spring 140will continue to act against annular lip 146 of seal plate 132 to urgesurface 144 against O-ring 138 to provide a seal preventing the flow offuel vapor out of vehicle fuel tank 14, and torsion spring 200 willstill act against inwardly-facing surface 202 of flapper door 180 tourge sealing surface 196 into sealing engagement against annular valveseat 156 to prevent the flow of ambient air into vehicle fuel tank 14.This construction is intended to maximize the likelihood that fillerneck 12 will remain sealed even if closure assembly 10 is subjected toan impact that causes separation of outer shell 30 and flange 100 fromouter body 32.

Certain robotic refueling systems 16 use filler neck detector 26 todetermine the location of closure assembly 10. Filler neck detector 26can use computer vision and recognition technology to determine thelocation of closure assembly 10, in which case externalnozzle-positioning sensor 28 would include a camera positioned to viewclosure assembly 10 from in front of front wall 70 as shown in FIG. 18.To accommodate filler neck detector 26, outer shell 30 is made from amaterial having a light color and flapper door 180 is made from amaterial having a contrasting dark color. This provides closure assembly10 with a “bulls-eye” appearance from the vantage point of the camera asshown in FIG. 18 that can easily and readily be recognized by computervision and recognition technology.

Although the preferred outer shell 30 and flapper door 180 present agenerally “bulls-eye” pattern for detection by computer vision andrecognition technology, it is within the scope of the invention aspresently perceived to provide any pattern of contrasting shades, eithera light pattern on a dark background or a dark pattern on a lightbackground, as seen from a front elevation view of closure assembly 10.It is important that the contrast is sufficient to permit a computervision and recognition system to distinguish the pattern from thebackground. It is, therefore, within the scope of the invention aspresently perceived to provide a pattern of nearly any shape or apattern including several shapes such as stripes, dots, dashes, arrows,or any combination of these or other contrasting designs that can beprovided on or near the face of closure assembly 10 and detected byfiller neck detector 26.

Outer shell 30 can be made from a material having a dark color andflapper door 180 can be made from a material having a contrasting lightcolor. This configuration was not chosen for the preferred embodimentbecause flapper door 180 may darken with use-related contact and wearand may, as a result, eventually fail to provide the desired contrast.

Closure assembly 10 can be mounted on a vehicle 22 having a fuel door260 and a dust cover 262 mounted on fuel door 260 as shown in FIG. 19.Dust cover 262 has an axially inwardly-facing surface 264 engagingboot-seating surface 78 of outer shell 30. Dust cover 262 is connectedto fuel door 260 and is positioned to move away from outer shell 30 whenfuel door 260 swings to an opened position. Dust cover 262 is typicallymade from an open cell foam pad, through any material that can bemounted on fuel door 260 to cover outer shell 30 and reduce the amountof dust that collects in closure assembly 10 can be used.

Although the invention has been described in detail with reference topreferred embodiments, variations and modifications exist within thescope and spirit of the invention as described and defined in thefollowing claims.

I claim:
 1. A filler neck closure assembly for a vehicle fuel tankfiller neck, the assembly comprising a closure for closing the fillerneck, the closure including a housing formed to include an interiorregion for receiving fuel vapor in the filler neck and a vent aperturefor discharging fuel vapor from the interior region, closure retainerapparatus appended to the housing and configured to engage the fillerneck when the housing is installed in the filler neck to block removalof the closure from the filler neck, a seal member engaging the housingand lying in a position to engage the filler neck to establish a sealedconnection between the housing and the filler neck when the housing isinstalled in the filler neck, and a movable tank pressure controlassembly mounted for movement in the interior region of the housingbetween a filler neck-closing position blocking discharge of fuel vaporin the filler neck through the vent aperture and a filler neck-ventingposition allowing discharge of fuel vapor in the filler neck through thevent aperture, the movable tank pressure control assembly including anozzle-receiving opening and a door mechanism normally closing thenozzle-receiving opening.
 2. The assembly of claim 1, further comprisingan outer shell formed to include a nozzle-receiving opening aligned withthe nozzle-receiving opening formed in the movable tank pressure controlassembly to allow a fuel pump nozzle to pass through saidnozzle-receiving opening and open the door mechanism to reach theinterior region of the housing, the outer shell being mounted on thehousing for rotation about an axis passing through the interior regionof the housing to allow the outer shell to be rotated relative to thehousing to a predetermined orientation relative to the housing.
 3. Theassembly of claim 2, wherein the closure retainer apparatus includesannular flanges for rotatably engaging the filler neck and furthercomprising a torque-override mechanism engaging the outer shell andhousing and providing a torque-limited driving connection between theouter shell and the housing when the outer shell is rotated in acap-advancing direction.
 4. The assembly of claim 2, wherein thetorque-override mechanism includes a resilient finger cantilevered tothe housing, a driven tooth appended to the resilient finger to movetherewith relative to the housing, and a plurality of drive teethappended to the outer shell and positioned to engage the driven tooth onthe resilient finger in response to rotation of the outer shell aboutthe axis of rotation.
 5. The assembly of claim 4, wherein the housingincludes a body engaging the seal member and a frangible sectioninterconnecting the body and the resilient finger to support theresilient finger in a cantilevered position relative to the housing. 6.The assembly of claim 3, wherein the torque-override mechanism includesa plurality of resilient fingers cantilevered to the housing, a driventooth appended to each resilient finger, and a plurality of drive teethappended to the outer shall and positioned to engage the driven teeth onthe resilient fingers in response to rotation of the outer shell aboutthe axis of rotation.
 7. The assembly of claim 6, wherein the housingincludes a body engaging the seal member and a frangible sectioninterconnecting the body and each of the resilient fingers to supportthe resilient fingers in cantilevered positions relative to the housing.8. The assembly of claim 3, wherein the housing includes an outer bodytermed formed to include the vent aperture and the torque-overridemechanism includes a resilient finger cantilevered to the outer body, adriven tooth appended to the resilient finger, and a plurality of driveteeth appended to the outer shell and positioned to engage the driventooth on the resilient arm in response to rotation of the outer shellabout the axis of rotation.
 9. The assembly of claim 2, wherein theouter shell includes a side wall having an annular outer edge and afront wall appended to the annular outer edge and formed to include thenozzle-receiving opening formed in the outer shell, the side wall andthe front wall cooperate to define an enclosed space receiving anaxially outer portion of the housing therein.
 10. The assembly of claim9, wherein the front wall includes a nozzle-guiding surface inclinedwith respect to the axis of rotation and positioned to lie between theannular outer edge of the side wall and the nozzle-receiving openingformed in the outer shell.
 11. The assembly of claim 9, wherein theouter shell further includes a plurality of drive teeth positioned tolie in the enclosed space and engage the housing to provide a rotationaldriving connection between the outer shell and the housing.
 12. Theassembly of claim 9, further comprising a torque-override mechanismengaging the outer shell and housing in the enclosed space and providinga torque-limited driving connection between the-outer the outer shelland the housing.
 13. The assembly of claim 9, wherein the side wallincludes an annular interior surface and the housing includes an annularflange lying in the enclosed space and having an annular outer edgeabutting the annular interior surface of the side wall in rotativebearing engagement.
 14. The assembly of claim 13, wherein the housingincludes a body engaging the seal member and a frangible sectioninterconnecting the body and the annular flange.
 15. The assembly ofclaim 13, wherein the housing includes a body formed to include theinterior region and the annular flange includes an inner edge appendedto the body.
 16. The assembly of claim 13, wherein the housing includesa body formed to include the interior region and the annular flange iscoupled to the body, and further comprising a torque-override mechanismlying in the enclosed space and including a resilient fingercantilevered to the annular flange, a driven tooth appended to theresilient finger to move therewith in the enclosed space relative to theannular flange, and a plurality of drive teeth appended to the outershell to lie in the enclosed space and engage the driven tooth on theresilient finger in response to rotation of the outer shell relative tothe housing about the axis of rotation.
 17. The assembly of claim 16,wherein the housing further includes a frangible section appended to thebody and the annular flange is coupled to the body by the frangiblesection.
 18. The assembly of claim 13, wherein the housing is formed toposition the vent aperture to pen into the enclosed space in closeproximity to the annular flange.
 19. The assembly of claim 2, whereinthe outer shell is formed to include a spline-receiving space and themovable tank pressure control assembly is formed to include a splinereceived in the spline-receiving space formed in the outer shell so thatthe movable tank pressure control assembly is keyed to rotate with theouter shell relative to the housing in response to rotation of the outershell about the axis of rotation.
 20. The assembly of claim 19, whereinthe outer shell includes a side wall having an annular outer edge and afront wall appended to the annular outer edge and formed to include thenozzle-receiving opening formed in the outer shell, the side wall andthe front wall cooperate to define an enclosed space receiving anaxially outer portion of the housing therein, and the outer shellfurther includes lugs positioned to lie in the enclosed space to definethe spline-receiving space therebetween.
 21. The assembly of claim 19,wherein the movable tank pressure control assembly includes apressure-relief seal plate having an annular lip and an annular guidewall appended to the annular lip, a spring lying around the annularguide wall and yieldably biasing the annular lip to urge the annular lipto a normally closed position engaging the housing to establish thefiller neck-closing position of the movable tank pressure controlassembly, and the spline is appended to the annular guide wall.
 22. Theassembly of claim 19, whereto wherein the outer shell includes a sidewall and a front wall appended to the side wall, the front wall isformed to include the nozzle-receiving opening formed in the outershell, an interior surface facing toward the movable tank pressurecontrol assembly, an exterior surface defining a nozzle-guiding surfaceterminating at the nozzle-receiving opening, and a lug appended to theinterior surface to define an outer boundary of the spline-receivingspace and positioned to engage the spline included in the movable tankpressure control assembly during rotation of the outer shell relative tothe housing about the axis of rotation.
 23. The assembly of claim 1,wherein the housing includes an inner body carrying the closure retainerapparatus and an outer body coupled to the inner body to define theinterior region therebetween and formed to include the vent aperture andan outer opening receiving the movable tank pressure control assembly topermit insertion of a fuel-dispensing nozzle into the interior region ofthe housing through the nozzle-receiving opening.
 24. The assembly ofclaim 23, wherein the inner body includes a cylindrical sleeve having anouter end adjacent to the movable tank pressure control assembly, anopposite inner end, and an exterior surface extending between the innerand outer ends, the closure retainer apparatus includes an annularflange appended to the exterior surface and configured to rotatablyengage the filler neck, the inner body further includes a radiallyoutwardly extending annular lip appended to the outer end of thecylindrical sleeve and having an axially inner surface facing in a firstdirection toward the annular flange and an axially outer surface facingin an opposite second direction, and the seal member lies around thecylindrical sleeve to abut the axially inner surface of the radiallyoutwardly extending annular lip and the exterior surface of thecylindrical sleeve in a position lying between the annular flange andthe annular lip.
 25. The assembly of claim 24, wherein the movable tankpressure control assembly includes an annular seal abutting the axialouter surface of the annular lip, a pressure-relief seal plate formed toinclude the nozzle-receiving opening, and a spring yieldably biasing thepressure-relief seal plate to a normally closed position engaging theannular seal to block discharge of fuel vapor in the inner body throughthe vent aperture.
 26. The assembly of claim 23, further comprising anouter shell formed to include an interior region receiving a portion ofthe outer body and a nozzle-receiving opening communicating with thenozzle-receiving opening formed in the movable tank pressure controlassembly, the outer shell being mounted on the outer body for rotationrelative to the outer body about an axis of rotation, and atorque-override mechanism engaging the outer shell and outer body andproviding a torque-limited driving connection between the outer shelland outer body when the outer shell is rotated about the axis ofrotation in a cap-advancing direction.
 27. The assembly of claim 26,wherein the outer shell is formed to include a spline-receiving spaceand the movable tank pressure control assembly is formed to include aspline received in the spline-receiving space formed in the outer shellso that the movable tank pressure control assembly is keyed to rotatewith the outer shell relative to the housing in response to rotation ofthe outer shell about the axis of rotation.
 28. The assembly of claim 1,wherein the movable tank pressure control assembly includes apressure-relief seal plate formed to include the nozzle-receivingopening formed in the movable tank pressure control assembly and aspring engaging the housing and the pressure-relief seal plate toyieldably urge the pressure-relief seal plate to a normally closedposition against the housing to establish the filler neck-closingposition of the movable tank pressure control assembly.
 29. The assemblyof claim 28, wherein the door mechanism includes a vacuum-relief valvecoupled to the pressure-relief seal plate for movement between a closedposition closing the nozzle-receiving opening and an open positionopening the nozzle-receiving opening and a spring yieldably biasing thevacuum-relief valve to the closed position.
 30. The assembly of claim28, wherein the housing includes an exterior surface abutting the sealmember and an interior surface lying in the interior region, the movabletank pressure control assembly further includes an annular seal engagingthe interior surface, and the spring is configured to yieldably urge thepressure-relief seal plate against the annular seal to establish thefiller neck-closing position and partition the interior region into aninner chamber positioned to communicate with the filler neck and anouter chamber communicating with the vent aperture formed in thehousing.
 31. The assembly of claim 30, wherein the spring is positionedto lie in the outer chamber.
 32. The assembly of claim 28, furthercomprising an outer shell formed to include an interior region receivinga portion of the housing and a nozzle-receiving opening communicatingwith the nozzle-receiving opening formed in the pressure-relief sealplate, the outer shell being mounted on the housing for rotationrelative to the housing about an axis of rotation, the outer shell beingformed to include a spline-receiving space, and the pressure-relief sealplate including a spline received in the spline-receiving space formedin the outer shell so that the pressure-relief seal plate is keyed torotate with the outer shell relative to the housing in response torotation of the outer shell about the axis of rotation.
 33. A fillerneck closure assembly for a vehicle fuel tank filler neck, the assemblycomprising a housing configured to mount in the filler neck and formedto include a sealing surface, and a pressure-relief valve positioned tolie in the housing, the pressure-relief valve including anozzle-receiving portion and a sealing portion, the nozzle-receivingportion being formed to include a nozzle-receiving opening sized toreceive a pump nozzle during refueling of the fuel tank the sealingportion being movable relative to the housing between a closure-sealingposition sealingly engaging the sealing surface and a pressure-reliefposition away from the sealing surface to define an opening therebetweento vent fuel vapor from the fuel tank when tank pressure exceeds apredetermined maximum pressure, the nozzle-receiving portion movingaxially with the sealing portion during movement of the sealing portionbetween the closure-sealing position and the pressure-relief position,and wherein the housing is formed to include a passageway extendingtherethrough and containing the pressure-relief valve therein, thehousing and the pressure-relief valve cooperate to define an annularspace around the pressure-relief valve and between the pressure-reliefvalve and the housing, and a coiled compression spring is positioned inthe annular space, the pressure-relief valve includes an axiallyoutwardly extending annular guide wall adjacent to the annular space andthe guide wall defines a radially inner side of the annular space, thehousing further includes a radially inwardly extending annular lipappended to the housing and the guide wall slidingly engages the lip ofthe housing to radially guide the pressure-relief valve during movementof the pressure-relief valve between the closure-sealing position andthe pressure-relief position.
 34. A filler neck closure assembly for avehicle fuel tank filler neck, the assembly comprising a housingconfigured to mount in the filler neck and formed to include a sealingsurface, a pressure-relief valve positioned to lie in the housing, thepressure-relief valve including a nozzle-receiving portion and a sealingportion, the nozzle-receiving portion being formed to include anozzle-receiving opening sized to receive a pump nozzle during refuelingof the fuel tank, the sealing portion being movable relative to thehousing between a closure-sealing position sealingly engaging thesealing surface and a pressure-relief position away from the sealingsurface to define an opening therebetween to vent fuel vapor from thefuel tank when the tank pressure exceeds a predetermined maximumpressure, the nozzle-receiving portion moving axially with the sealingportion during movement of the sealing portion between theclosure-sealing position and the pressure-relief position, the housingbeing formed to include a passageway extending therethrough andcontaining the pressure-relief valve therein, the pressure-relief valveincluding an axially outwardly extending annular guide wall, the housingand the pressure-relief valve cooperating to define an annular spacearound the annular guide wall of the pressure-relief valve and betweenthe annular guide wall and the housing the annular guide wall beingadjacent to the annular space to dating define a radially inner side ofthe annular space, a coiled compression spring positioned to lie in theannular space and surround the annular guide wall between the sealingportion of the pressure-relief valve and the annular lip of the housing,and an outer shell rotatably connected to the housing, the outer shallshell including a plurality of axially inwardly directed drive teeth,the housing further including a plurality of driven teeth and means forbiasing the driven teeth axially outwardly, the driven teeth beingconfigured to engage the drive teeth to provide a torque-limitedconnection between the outer shell and the housing when the outer shellis rotated in a closure-advancing direction.
 35. The assembly of claim34, wherein the drive teeth on the outer shell are positioned to lieradially outwardly of the coiled compression spring.
 36. A filler neckclosure assembly for a vehicle fuel tank filler neck, the assemblycomprising a housing configured to mount in the filler neck and formedto include a sealing surface, and a pressure-relief valve positioned tolie in the housing, the pressure-relief valve including anozzle-receiving portion and a sealing portion, the nozzle-receivingportion being formed to include a nozzle-receiving opening sized toreceive a pump nozzle during refueling of the fuel tank, the sealingportion being movable relative to the housing between a closure-sealingposition sealingly engaging the sealing surface and a pressure-reliefposition away from the sealing surface to define an opening therebetweento vent fuel vapor from the fuel tank when tank pressure exceeds apredetermined maximum pressure, the nozzle-receiving portion movingaxially with the sealing portion during movement of the sealing portionbetween the closure-sealing position and the pressure-relief position,wherein the housing is formed to include a radially inwardly extendinglip appended to an axially outer portion of the housing, the filler neckclosure further comprises a spring engaging the lip of the housing madand the pressure-relief valve to yieldably bias the pressure-reliefvalve toward the closure-sealing position, an outer shell adjacent to anaxial outer end of the housing, and a radially outwardly extendingflange appended to the housing and interconnecting the outer shell andthe housing, the flange including a frangible section configured tofracture in response to an impact to the outer shell leaving the housingintact to seal the filler neck, the flange being appended to the housingaxially adjacent to the lip.
 37. The assembly of claim 36, wherein thelip is integrally appended to an axially upper edge of the housing, theflange is formed to include a groove to define the frangible portion ofthe flange, and the groove is formed to lie adjacent to the radiallyouter edge of the lip.
 38. A filler neck closure assembly for a vehiclefuel tank filler neck, the assembly comprising a housing configured tomount in the filler neck, the housing being formed to include aninterior region having an outlet in fluid communication with the fillerneck and a vent aperture for discharging fuel vapor extant in theinterior region from the housing, an outer shell rotatably coupled tothe housing, a pressure-relief valve movable relative to the housingbetween a closed position partitioning the interior region to define aninner chamber communicating with the outlet and an outer chambercommunicating with the vent aperture and blocking the flow of fuel vaporfrom the inner chamber to the outer chamber and a pressure-reliefposition allowing the flow of fuel vapor from the inner chamber to theouter chamber to vent fuel vapor from the fuel tank through the interiorregion of the housing and the vent aperture formed in the housing whentank pressure exceeds a predetermined maximum pressure, and a splineinterposed between the outer shell and the housing, the spline impartingrotational movement from the outer shell to the pressure-relief valve torotate the pressure-relief valve relative to the housing in response torotational movement of the outer shell relative to the housing, thespline blocking independent rotational movement of the outer shellrelative to the pressure-relief valve.
 39. The assembly of claim 38,wherein the outer shell is formed to include a spline-receiving spaceand the spline is appended to the pressure-relief valve and the splineis received in the spline-receiving space.
 40. The assembly of claim 38,wherein the outer shell includes an axis of rotation and a front wallformed to include an outer opening sized to receive a pump nozzle duringrefueling of the fuel tank, the outer opening includes a first centralaxis coincident with the axis of rotation of the outer shell, and thepressure-relief valve is formed to include an inner opening sized toreceive a pump nozzle during refueling of the fuel tank, the inneropening having a second central axis spaced apart from the first centralaxis.
 41. The assembly of claim 40, further comprising a base positionedto lie between the filler neck and the housing, the base including anaxially inner wall formed to include an unleaded discriminator openingsized to receive a pump nozzle during refueling of the fuel tank, theouter opening, the inner opening, and the unleaded discriminator openingeach being positioned to receive the pump nozzle during refueling of thefuel tank.
 42. The assembly of claim 38, further comprising a circularplate pivotably appended to the pressure-relief valve and movablebetween a closed position engaging the pressure-relief valve and a fullyopen position away from the pressure-relief valve, the pressure-reliefvalve being formed to include a nozzle-receiving opening sized toreceive a pump nozzle, during refueling of the fuel tank, the circularplate covering the nozzle-receiving opening when the circular plate isin the closed position and engaging the pump nozzle when in the fullyopen position during refueling of the fuel tank.
 43. The assembly ofclaim 42, further comprising a spring mounted in the housing andengaging the circular plate to yieldably bias the circular plate towardthe closed position, the spring acting through the circular plate toyieldably bias the pump nozzle radially outwardly during refueling ofthe fuel tank.
 44. A filler neck closure assembly for a vehicle fueltank filler neck, the assembly comprising a housing configured to mountin the filler neck and formed to include an interior region and asealing surface, a pressure-relief valve positioned to lie in theinterior region of the housing, the pressure-relief valve being movablerelative to the housing between a closure-sealing position sealinglyengaging the sealing surface and a pressure-relief position away fromthe sealing surface to define an opening therebetween to vent fuel vaporfrom the fuel tank when tank pressure exceeds a predetermined maximumpressure, and an outer shell mounted on the housing for rotation aboutan axis passing through the interior region formed in the housing, theouter shell including a side wall and a front wall cooperating with theside wall to define an enclosed space receiving an axially outer portionof the pressure-relief valve when the pressure-relief valve is in thepressure-relief position.
 45. The assembly of claim 44, wherein thefront wall is further formed to include axially inwardly cantilevereddrive teeth positioned to lie in the enclosed space of the outer shelland engaging the housing to provide a rotational driving connectionbetween the outer shell and the housing.
 46. The assembly of claim 44,wherein the front wall is further formed to include a funnel-shapednozzle-guiding surface to guide the radial movement of the pump nozzletoward the nozzle-receiving opening as the pump nozzle advances axiallytoward the nozzle-receiving opening during refueling of the fuel tank.47. The assembly of claim 44, further comprising a torque-overridemechanism for providing a torque-limited connection between the outershell and the housing so that the outer shell rotates independently ofthe housing upon the application of torque above a predetermined maximumtorque on the outer shell, the torque-override mechanism being appendedto the outer shell and the housing and positioned to lie in the enclosedspace defined by the side wall and front wall of the outer shell. 48.The assembly of claim 44, wherein the pressure-relief valve is formed toinclude a spline, the outer shell is rotatably coupled to the housingand is formed to include a spline-receiving space, and the spline isreceived in the spline-receiving space so that the pressure-relief valverotates with the outer shell relative to the housing when the outershell rotates relative to the housing.
 49. The assembly of claim 48,further comprising a flapper door and a spring engaging the flapper doorto yieldably bias the flapper door against the nozzle-receiving portionto cover the nozzle-receiving opening, the flapper door being pivotablyconnected to the pressure-relief valve and arranged to rotate relativeto the housing with the pressure-relief valve when the pressure-reliefvalve rotates relative to the housing in response to rotation of theouter shell relative to the housing.
 50. The assembly of claim 44,further comprising a base interposed between the filler neck and thehousing and a sealing gasket interposed between the base and the housingand sealingly engaging the base and the housing to block the flow ofliquid fuel, fuel vapor, and air therebetween.
 51. The assembly of claim50, wherein the housing is formed to include an inner body received bythe base and an outer body connected to the inner body and the outershell is connected to the outer body.
 52. The assembly of claim 51,wherein the outer body is formed to include an interior region, theinner body is formed to include an interior region in fluidcommunication with the interior region of the outer body, and thepressure-relief valve is received in the interior region of the outerbody.
 53. The assembly of claim 51, further comprising an o-ring sealmounted on the sealing surface to provide a seal between thepressure-relief valve and the inner body of the housing thereby blockingthe flow of liquid fuel, fuel vapor, and air therebetween when thepressure-relief valve is in the closure-sealing position, the inner bodyof the housing being formed to include a radially outwardly extendingannular lip having an axially outwardly facing surface including thesealing surface and engaging the o-ring seal and an axiallyinwardly-facing surface engaging the sealing gasket.
 54. The assembly ofclaim 44, wherein the side wall is formed to include an axially inneredge lying in a first plane and an axially outer edge lying in a secondplane that is inclined relative to the first plane.
 55. The assembly ofclaim 54, wherein the front wall is formed to include a nozzle-receivingopening sized to receive a pump nozzle during refueling of the fuel tankand a funnel-shaped nozzle-guiding surface to guide the radial movementof the pump nozzle toward the nozzle-receiving opening as the pumpnozzle advances axially toward the nozzle-receiving opening duringrefueling of the fuel tank.
 56. A filler neck closure assembly for avehicle fuel tank filler neck, the filler neck closure assemblycomprising a housing configured to mount in the filler neck, a closureportion mounted in the housing and having an aperture for receiving anozzle to introduce fuel into the filler neck, a plate, means forsupporting the plate for movement relative to the closure portionbetween a closed position blocking the flow of air through the aperturemeans and an open position allowing the flow of air through the aperturemeans when the tank pressure is less than a predetermined minimumpressure, the supporting means being appended to the closure portion, aspring lying in the housing and yieldably biasing the plate against theclosure portion, the spring having a spring constant such that the platesealingly engages the closure portion when the tank pressure is abovethe predetermined minimum pressure and such that the plate disengagesfrom the closure portion when tank pressure is below the predeterminedminimum pressure to form an opening therebetween allowing the flow ofair through the aperture means, through the opening, and into the fueltank, the closure portion being formed to include a spline, and an outershell rotatably connected to the housing and formed to include aspline-receiving space positioned to receive the spline so that theclosure portion rotates relative to the housing with the outer shell asthe outer shell rotates relative to the housing.
 57. A filler neckclosure assembly for a vehicle fuel tank filler neck, the filler neckclosure assembly comprising a housing configured to mount in the fillerneck, a closure portion mounted in the housing and having aperture meansfor receiving a nozzle to introduce fuel into the filler neck, a plate,means for supporting the plate for movement relative to the closureportion between a closed position blocking the flow of air through theaperture means and an open position allowing the flow of air through theaperture means when the tank pressure is less than a predeterminedminimum pressure, the supporting means being appended to the closureportion, a spring lying in the housing and yieldably biasing the plateagainst the closure portion, the spring having a spring constant suchthat the plate sealingly engages the closure portion when the tankpressure is above the predetermined minimum pressure and such that theplate disengages from the closure portion when tank pressure is blow thepredetermined minimum pressure to form an opening therebetween allowingthe flow of air through the aperture Weans, through the opening, andinto the fuel tank, the closure portion being mounted for movementrelative to the housing between a closed position blocking the flow offuel vapor between the housing and the closure portion and an openposition allowing the flow of fuel vapor between the closure portion andthe housing when the tank pressure is above a predetermined maximumpressure, and a compression spring yieldably biasing the closure portiontoward the closed position, the compression spring having a first endengaging the closure portion, a second end engaging the housing, and thecompression spring being positioned to lie axially outward of the springyieldably biasing the plate against the closure portion.
 58. A fillerneck closure assembly for a vehicle fuel tank filler neck, the assemblycomprising a housing configured to be received by the filler neck, asealing gasket positioned to lie between the housing and the fillerneck, the sealing gasket being subject to damage due to overtighteningof the closure assembly on the filler neck, an outer shell rotatablyconnected to the housing, the outer shell being formed to include anozzle-receiving opening, and a torque-override mechanism for providinga torque-limited connection between the outer shell and the housing toprotect the gasket from over tightening of the closure assembly on thefiller neck resulting from the application of torque above apredetermined maximum torque on the outer shell, the torque-overridemechanism including drive teeth appended to the outer shell.
 59. Theassembly of claim 58, further comprising a base disposed in the fillerneck between the filler neck and the housing, the base being formed toinclude a mouth having a lip arranged to engage the sealing gasket andan axially inner wall having an unleaded discriminator.
 60. The assemblyof claim 58, wherein the torque-override mechanism further includes aflange appended to the housing, the flange having a plurality of driventeeth and a spring for yieldably biasing the driven teeth axiallyoutwardly, and the driven teeth are configured to engage the driveteeth.
 61. The assembly of claim 60, wherein the spring includesresilient fingers connected to the flange and cantilevered therefrom andthe driven teeth are appended to the resilient fingers.
 62. The assemblyof claim 58, wherein the drive teeth are spaced apart along a generallycircular path that is positioned to lie radially outwardly of thesealing gasket.
 63. The assembly of claim 58, wherein the outer shell isformed to include a front wall arranged to define a generallyfunnel-shaped nozzle-guiding surface terminating at the nozzle-receivingopening.
 64. The assembly of claim 63, further comprising a latchingportion integrally appended to the front wall and positioned to engagethe pump nozzle during refueling of the fuel tank to prevent inadvertentaxial movement of the pump nozzle out of the nozzle-receiving opening.65. The assembly of claim 58, wherein the outer shell is formed toinclude a front wall arranged to define a generally planar boot-seatingsurface adjacent to the nozzle-receiving opening.
 66. A self-closing capadapted to be mounted onto a filler neck of a fuel tank of an automotivevehicle wherein said neck includes a restrictive flap pivotallyconnected thereto, comprising: a closure ring having an annular body andmeans for detachably mounting the periphery of said annular body arounda peripheral edge of a filler neck, a closure flap assembly including acircular member having an opening for receiving a nozzle, a closureflap, means for pivotally mounting an edge of said closure flap oversaid opening, and means for affixing said circular member to saidannular body such that the orientation of said pivotal mounting means isadjustable relative to a pivotal connection between said restrictiveflap and said neck, and a cover means detachably mountable over saidclosure flap assembly.
 67. The self-closing cap as defined in claim 66 ,wherein said closure flap is spring biased over said opening in saidcircular member.
 68. The self-closing cap as defined in claim 66 ,wherein said means for affixing said circular member to said annularbody includes a ratchet lock mechanism.
 69. The self-closing cap asdefined in claim 66 , wherein said cover means includes a port forreceiving a nozzle and a guide face for guiding said nozzle into saidport.
 70. The self-closing cap as defined in claim 69 , wherein saidguide face is inclined with respect to said circular member of saidclosure flap assembly to facilitate the guiding of said nozzle into saidport.
 71. The self-closing cap as defined in claim 70 , wherein saidfiller neck is inclined at an oblique angle with respect to an adjacentwall of said vehicle, and said inclination of said guide face orientssaid face at an angle that facilitates the insertion of a fuel nozzlefrom an automatic filling machine.
 72. The self-closing cap as definedin claim 69 , wherein said cover means includes means for guiding thenozzle of an automatic fuel-dispensing machine.
 73. A self-closing capfor attachment to the fuel filler neck of a vehicle that is particularlyadapted for use with an automatic filling machine, said neck having arestrictive flap within its inner diameter that is connected thereto bya pivotal connection, comprising: a closure ring having an annular bodyand means for detachably mounting the periphery of said annular bodyaround the periphery of a filler neck, a closure flap assembly includinga circular member having an opening, a closure flap, means for pivotallymounting said closure flap over said opening, and means for affixingsaid circular member at a selected position with respect to theperiphery of said annular body of said closure ring after said ring hasbeen mounted around the periphery of said filler neck such that theorientation of said pivotal mounting means is angularly adjustablerelative to said annular body to a position substantially 180° oppositefrom said pivotal connection of said restrictive flap, and a cover meansdetachably mountable over said closure flap assembly.
 74. Theself-closing cap as defined in claim 73 , wherein both said restrictiveflap and said closure flap are spring biased over said neck innerdiameter and opening, respectively, and wherein said 180° orientationbetween said pivotal connection and said pivotal mounting meansfacilitates the insertion and withdrawal of a fuel dispensing nozzlefrom an automatic filling machine through said cap and filler neck. 75.The self-closing cap as defined in claim 73 , wherein said affixingmeans includes a ratchet lock mechanism.
 76. The self-closing cap asdefined in claim 73 , wherein said cover means includes a port forreceiving a fuel nozzle, and a guide face for guiding said nozzle intosaid port.
 77. The self-closing cap as defined in claim 76 , whereinsaid guide face is inclined with respect to said circular member of saidclosure flap assembly to facilitate the guiding of said fuel nozzle intosaid port.
 78. The self-closing cap as defined in claim 77 , whereinsaid filler neck is inclined at an oblique angle with respect to anadjacent wall of said vehicle, and said inclination of said guide facefacilitates the insertion of said fuel nozzle into said port and throughsaid opening.
 79. The self-closing cap as defined in claim 77 , whereinsaid cover means includes means for guiding the nozzle of an automaticfuel dispensing machine.
 80. A self-closing cap adapted to be mountedonto a filler neck of a fuel tank of an automotive vehicle, comprising:a closure ring having an annular body and means for detachably mountingthe periphery of said annular body around a peripheral edge of a fillerneck, and a closure flap assembly including a circular member having anopening for receiving a nozzle, a closure flap, means for pivotallymounting an edge of said closure flap over said opening, and means forpermanently affixing said circular member to said annular body such thatthe orientation of said pivotal mounting means is angularly adjustablerelative to said annular body, and a cover means detachably mountableover said closure flap assembly.